Fan Not Working - HELP

[Glyn pickering]

Hi all

Starting to use the bike regularly now while still sorting the jetting on the carb.

I noticed this morning that the temp gauge didn't move at all on the way to work, even tho' the motor was really hot in rush hour traffic.
 Same story tonight. The fan came on very briefly in the morning as I parked the bike but nothing tonight.

I'm not keen to ride it in this stae incase I overheat it.

Any idea where to start looking for the problem?

Regards

Glyn
 ??? ??? ???

[Lucky]

The service manual is allways a good place to start, follow the diagnostics there, jump the fan directly to the battery to make sure it works.
Most common causes in order:

clean the contacts at the fan temperature switch located on the metal coolant line under the tank. with the key on, if you ground this lead, the fan should come right on. if it doesn't it's the switch itself or poor contact to it.

check for proper coolant level & "burp" it using the bolt on that same metal line. if coolant isn't touching that switch the fan won't come on.

if you ground the lead at the switch & the fan doesn't come on, first check the 10 A fuse located in the headlight bucket, if it's good (sometimes they look good & still are bad or "weak") then check the relay. often after 20 plus years they are full of rust & need to be cleaned out or replaced.

if none of these does the trick, you'll have to investigate further, probably a wiring problem, but i doubt it.

most likely it's one of the above problems, but i have heard once that someone had a water pump impeller worn to the point that it wasn't moving enough coolant thru the system. rare, but possable.

--Lucky

[Glyn Pickering]

Thanks for that Lucky. I read the manual but it really didn't make too much sense to me.  

The radiator and hoses were nice and hot so I think the thermostat is still doing it's job OK. I won't ride it again till
I've found the problem.

Regards

Glyn

[louthepou]

Hi Glyn,

I am proof that Lucky's "relay" possibility is real. I had that problem two years ago. In my case, after making the checks outlined in the Haynes (re-reading them often, cause I too was a bit confused), I ended up finding it was the faulty relay.

[Lucky]

Glyn, if you need help finding the manuals, I can help.  send me an email. i tried to send you one but it bounced.
--Lucky

[Glyn Pickering]

Thanks for the offer Lucky. I have the Haynes manual which is pretty good for most things.

I'm on pickteam@xtra.co.nz   - all small case.

Cheers again

Glyn

[Glyn Pickering]

Just a quick note to say everything working now.

There was a fair bit of corrosion on both the sensors in the allot T piece. After a good clean we're  cooking again.

Thanks Guys.

Glyn

[Rick G]

My fan stopped working last summer in OR. so  did the drill and found that the sensor was bad . When I tried to remove it it broke off at the manifold , so not wanting to go through the hastle of changing the manifold in the middle of the riding season , i simply added a rocker switch to power the fan when ever in traffic. Works like a charm.